1. Field of the Invention
The present invention relates to a cable closure for protecting a junction point of two communication cables from water and external force (e.g. tensile, compressive, or vibrational force) applied between the two cables.
2. Description of the Prior Art
In usual, two communication cables are connected to each other by removing a cable sheath from a cable to expose a cable core and by connecting the two exposed cable cores. In this case, since it is necessary to protect the cable junction point from water and external force, a cable closure of airtight structure is attached to the cable junction point.
In addition, the cable and cable closure thereof are often filled with pressurized gas (e.g. air, nitrogen gas, etc. of about 1 at.) in order to improve the waterproof reliability thereof, which is called "gas maintenance". In this case, the cable closure is further required to prevent the pressurized gas from leaking from the inside to the outside thereof. Further, since there exist various cables of different diameters, there exists another requirement that the cable closure must be applicable to any junction points of cables of various diameters. Further, the cable are usually laid down in open air, there exist other requirements for sufficient durability, easy assembly/disassembly work, high strength, etc. in addition to the above-mentioned airtightness.
In the prior art cable closure, however, since cable junction point is protected from an external force by cable gripping members fixed to the cable core through slits formed in the cable sheath, and from water by non-elastic adhesive sealing tape material placed in spaces between the cable, elastic end plates, and sleeve, there exist various problems in that (a) firstly, various end plates must be prepared according to cables of different diameters and further the sleeve must be fastened against the elastic end plates by a great force for providing airtightness, thus resulting in a hard assembling work; (b) secondly, various-sized cable gripping members must be prepared according to cables of different diameters and plural slits must be formed in the cable sheath; (c) thirdly, since the non-elastic adhesive sealing tape material is used, it takes much time to disassemble the assembled cable closure; (d) finally, since the sealing washers for preventing the flow of the non-elastic sealing material are required, a great number of the components are needed to assemble the final cable closures, resulting in time consumption.
The arrangement of the prior-art cable closure and its drawbacks will be described in more detail hereinafter with reference to FIGS. 1(A), (B) and (C) under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT.